During the past year our efforts have been aimed at establishing characteristic changes of parotid and pancreatic acinar cells from rats that had been subjected to either hypoxia or sublethal doses of fluorouracil as a means of affecting ribonucleic acid synthesis. This phase of work has come close to a conclusion and we are now concentrating on ways to develop means by which the recovery of these glands from such a detrimental effects could be enhanced by using synthetic polyribonucleotides (poly R). Preliminary work has shown that administration of poly R homopolymers at 24 hours prior to sacrifice would enhance the protein synthesis by ascinar cells of the parotid and pancreas in hypoxid but not in control rats. Inasmuch as the precise mechanism of poly R actin is not clearly understood, our efforts in the coming year will concentrate on distinguishing the differential effects of various forms of poly R with different molecular configurations. The experimental methods used will include electron microscope studies of affected cells, and evaluation of amylase and protein synthesis as expressed per microgram of DNA. Data will be analyzed in light of the results that have been gained during the past year.